Search

We report the colloidal synthesis of 2D SnTe nanosheets through precursor hot-injection in a nonpolar solvent. During the reaction, an important intermediate - Sn-template - is formed which defines the confined growth of SnTe. This "flake-like" structure gives the first evidence for the possible 2D morphology formation prior to the anion precursor injection (TOP-Te). Additionally, we explore the role of each ligand in the reaction process. Thus, we explain the formation and morphology evolution of 2D SnTe nanostructures from a mechanism perspective as well as the role of each ligand on the molecular scale. The interplay of ligands provides the necessary conditions for the realization of stable low-dimensional SnTe nanomaterials with tunable size and shape.

We report a structural reconstruction-induced high photoluminescence quantum yield of 25% in colloidal two-dimensional tin iodide nanosheets that are synthesized by a hot-injection method. The as-synthesized red-colored nanosheets of octylammonium tin iodide perovskites at room temperature transform to white hexagonal nanosheets upon washing or exposure to light. This structural change increases the bandgap from 2.0 eV to 3.0 eV, inducing a large Stokes shift and a broadband emission. Further, a long photoluminescence lifetime of about 1 microsecond is measured for the nanosheets. Such long-lived broad and intense photoluminescence with large Stokes shift is anticipated to originate from tin iodide clusters that are formed during the structural reconstruction. Stereoactive 5s2 lone pair of tin (II) ions perturbs the excited state geometry of the white hexagonal nanosheets and facilitates the formation of self-trapped excitons. Such broadband and intensely emitting metal halide nanosheets are promising for white light-emitting diodes., Comment: 25 pagew, 5 figures